Identify the sampling technique used, and discuss potential so...

Question

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Questioning teachers as they leave a faculty lounge, a researcher asks 45 of them about their teaching styles.

Accepted Answer

Welcome back everyone. In this problem, to gather opinions on campus dining, a student stands outside the cafeteria at lunchtime and interviews 40 students who are leaving. What sampling technique is used and what are the potential sources of bias? A says is stratified sampling and there is no bias. B cluster sampling with selection bias. C simple random sampling with interviewer bias, and D convenience sampling with non-representative sample bias. Now, before we figure out which sampling technique is being used, let's define each of these sampling techniques. Now, to start in simple random sampling, OK. So let's, let's write that here. In simple random sampling, every individual in the population has an equal chance, OK? An equal chance of being selected. It could be, for example, drawing names from a hat, and this is best used when the population is small and homogeneous. Another type of sampling is known as stratified sampling. And in stratified sampling, we basically divide the population, OK? Into subgroups or strata based on shared characteristics like age, gender, location, and a random sample is taken from each subgroup. So an example of this could be when sampling students from each grade level in a school, and this is best used when you want representation from all key subgroups. Another type of sampling is known as cluster sampling, OK? And in this sample, like the name says, the population is divided into clusters. Often geographically and then entire clusters are randomly selected and all members of the selected clusters are surveyed. An example of this could be selecting 3 neighborhoods randomly and serving all households in each. This is best used when the population is large and spread out geographically. Another type of sampling is known as convenience sampling. OK. And in convenience sampling, basically we select individuals who are easiest to reach or, as the name suggests, most convenient. So this could be serving people or friends at the mall and it's best used when quick data is needed and accuracy is less critical. Know which one of our sampling techniques best fits this scenario in the problem statement. Well, notice here we're told that the students stands outside the cafeteria at lunchtime and interviews 40 students who are leaving. Now, in this case, our student is interviewing those who are easily accessible as they leave the cafeteria at lunchtime. This is convenient sampling. Now this method can lead to non-representative sample bias because it excludes students who do not eat at the cafeteria or who maybe eat at different times. So as a result, the opinions collected may not accurately reflect the views of the entire student body regarding campus dining. Therefore, D is the correct answer. Thanks a lot for watching everyone. I hope this video helped.

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.
Questioning teachers as they leave a faculty lounge, a researcher asks 45 of them about their teaching styles.

Key Concepts

Sampling Technique

Bias in Sampling

Generalizability

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